Drinking Water Supply
History
In 1951 the Municipality of Amsterdam bought the first dune areas
for the purpose of producing drinking water, followed by other
pieces of dune area during the 19th century. The first supply
of dune water dates from 1853, to the people of Amsterdam. Because
of the abstraction of the water the dune area became more and
more desiccated, with negative effects on flora, fauna and landscape.
In 1957 river water (from the Rhine) was infiltrated in the Amsterdam
Water Supply Dunes to overcome the desiccation and use the dunes
to naturally filter the river water to produce drinking water.
This however, had another big negative effect on nature: eutrophication.
The artificial input of river water caused damage to the ecological
quality of dune lakes and adjacent slacks as a result of a massive
increase in nutrients. Also, large areas were excavated to transport
the river water into the dunes. Therefore, since 1973 the river
water is piped from the River Rhine and infiltrated after intensive
pre-purification. In this day, 70 million m3 of drinking water
is extracted from the Amsterdam Water Supply Dunes, supplying
approximately 1,1 million users in the city of Amsterdam and its
surroundings.
Method
The water that is infiltrated in the Amsterdam Water Supply Dunes
is rainwater and water from the River Rhine, which is taken in
from the Lek canal at Nieuwegein. Along the River Rhine several
measuring stations are located, from Switzerland to the Netherlands.
These stations check the quality of the water. In case hazardous
substances are found, the intake of water stops immediately.
The water is pre-purificated before it is transported to the dunes.
The water is transported through 3 pipelines with a total length
of 210 kilometres into two small lakes at the east side of the
Amsterdam Water Supply dunes. From there, it streams into infiltration
canals, which are 35 metres wide and several kilometres long.
The water slowly infiltrates into the ground and raises the groundwater
level. The groundwater storage is enough to provide the city of
Amsterdam 2 months of drinking water. The water has a residence
time between 60 and 400 days and in this period natural, biological
processes purify the water.
Through drains the water is collected from the dunes into a canal,
from which the water streams to the Oranjekom (a small lake) under
natural fall. From the Oranjekom the water is pumped to the purification
plants. Here the water is further purificated to be used as drinking
water.
The drinking water is stored into two double storage tanks from
where it is distributed according to the need of the users. The
total net of water pipes is about 2000 kilometres long.
Water supply and nature management
Water abstraction and nature conservation are the two primary
functions of the Amsterdam Water Supply Dunes. Previous research
and future research is aimed at finding an optimum between water
abstraction and nature. It is not an option to stop the drinking
water production completely in favour of nature management. This,
because the dunes provide a safe storage and supply of water of
the highest quality.
Since 1989 an extensive multi-disciplinary research started in
combining water supply and nature management and in 1998 an eco-hydrological
survey was completed. Several projects have already been implemented
(see: Nature management).
There is also research being done about other ways to infiltrate
the water, for example deep-well-infiltration. This would allow
the infiltration canals to (partly) disappear and restoring the
original geomorphology in this part of the dunes. Benefits of
deep-well-infiltration are that the groundwater supply in the
deeper underground becomes larger and the chance of desiccation
of the current infiltration area at the surface becomes smaller.
Problems with deep-well-infiltration are the high cost and the
fact that the location of the deep-infiltration should be in the
dunes, because of the protection of the groundwater and the limited
size of the freshwater body beneath the dunes.
Result
Water abstraction provides a financially solid base for nature
conservation.
Nature conservation is an effective protection for water resources
and makes it possible to gain public support and trust.
References:
- Amsterdam Water Supply Dunes (1998) Amsterdam Water Supply
Dunes; Implementation of eco-hydrological research; in: Coastline
7-3, EUCC. (KJd)
- Beekelaar W.K.A.G. & Geelen L.H.W.T. (1999) Management
scheme 2000-2010; new challenges in the Amsterdam Watersupply
Dunes; in: (ed) Rabski K.: Connecting science and management
in the coastal zone; proceedings of the 7th EUCC International
conference Coastlines ’99, held in Miedzyzdroje, Poland, june
7-12 1999. (PC1999e#)
- Janssen M. (1993) Natuur in ontwikkeling; in: Duin: Themanummer
Amsterdamse Waterleidingduinen, no.1993-4, Stichting Duinbehoud.
(33BCD1993)
